The effect of a periodic source of a NO_x-SO₂ air pollution regime on the growth of forest trees was investigated. Radial increment growth studies were conducted to determine if correlations existed between emission levels of a source (predicted by production levels) and radial increment growth of forest trees. Three stands of loblolly pine, two of white pine, and one of sycamore proximal to the emission source were sampled by obtaining increment cores at d.b.h. (1.37 m from the base of the tree) from 50 trees in the dominant or codominant crown class of each stand. A multiple linear regression analysis utilizing annual radial increment growth as the dependent variable and the independent variables of annual production levels, total annual rainfall, annual seasonal rainfall, and age were used to evaluate all stands. An inverse relationship significant at the 0.001 level was demonstrated between growth and production levels in two loblolly pine stands and one white pine stand. The further analysis of these stands indicated respectively a 45%, 45%, and 10% theoretical reduction in diameter growth which was independent of symptom expression in white pine. Growth and production levels were not significantly correlated in the remaining loblolly pine stand and the sycamore stand; however, a positive relationship was exhibited in the second white pine stand. A field chamber study (utilizing charcoal filtered and nonfiltered air) with seedlings of red oak, sycamore, sweetgum, yellow poplar, white ash, green ash, and Virginia pine indicated significant inhibition of terminal elongation in Virginia pine and red oak in three locations surrounding the emission source. / Master of Science